JP2002005211A - Reaction adjustable gas spring - Google Patents

Abstract

PROBLEM TO BE SOLVED: To smoothly adjust gas pressure in a cylinder with a gas spring attached and further to secure smooth movement and sealing performance of a piston rod without changing its mounting length. SOLUTION: A reaction adjustable gas spring 10 comprises an adjust nut 31 which is screwed on an end of a cylinder mounting member 28 to be inserted into a cylinder 11 and is fitted to the cylinder 11 so as not to turn with respect to the cylinder 11, a seal member 34 which is connected to the adjust nut 31 in the cylinder 11 so as to seal the other end side of the cylinder 11, wherein gas pressure in the cylinder 11 can be adjusted by moving the seal member 34 via the adjust nut 31 through turning the cylinder 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reaction force adjusting type gas spring for assisting an opening operation force of a cover provided on a support.

[0002]

2. Description of the Related Art A gas spring assists the opening operation force of a lid by a reaction force of a compressed gas filled in a cylinder. The power fluctuates. For example, due to the expansion / contraction of gas due to temperature, the reaction force increases at high temperatures and decreases at low temperatures compared to room temperature. Therefore, a gas spring with the gas pressure set to a pressure suitable for warm regions is used in cold regions. , The reaction force decreases due to the decrease in the gas pressure, and the lid cannot be kept open. Conversely, when a gas spring whose gas pressure is set to a pressure suitable for a cold region is used in a warm region, the reaction force increases due to the increase in the gas pressure, and the operating force when closing the lid becomes excessive.

There is a gas spring described in Japanese Utility Model Publication No. 6-658 as a gas spring which can easily adjust the gas pressure in the cylinder when mounted on a vehicle body. One of the gas springs encloses a high-pressure gas in a cylinder including a cylinder main body and a cap screwed to the main body, and allows an adjustment rod having an auxiliary piston attached to the cylinder main body to advance and retreat from the cap side. In this case, the adjusting rod is inserted into the cap via a thrust bearing so as to be relatively rotatable, and is connected to the cap so as to be movable in the axial direction together with the cap (prior art 1). Another one of the gas springs seals high-pressure gas in a cylinder including a cylinder main body and a cap screwed to the main body, and allows a sub piston to advance and retreat to a cap side portion of the cylinder main body, and A piston inserted between the piston rod and the cylinder body in a sealable manner, and the sub-piston is connected to the cap via a thrust bearing so as to be relatively rotatable and axially movable together with the cap (prior art 2). It is.

[0004]

However, the prior art has the following problems. In both of the prior arts 1 and 2, the cap is screwed onto the cylinder body, and the cap is screwed to expand or contract the gas chamber volume of the cylinder body to adjust the gas pressure.
For this reason, the threaded portion (screw portion) of the cap is exposed on the outer surface of the cylinder main body constituting the cylinder, and dust or the like adheres to the threaded portion, easily impairing the screw operability of the cap, and reducing the gas pressure. Difficulty in smooth adjustment.

In the prior art 1, when the cap is rotated with the outer end of the adjusting rod being the attachment point to the vehicle body, the adjusting rod moves relative to the cylinder body, so that the mounting length of the gas spring changes. The degree of opening (the maximum opening angle, etc.) of the lid changes.

In prior art 2, a sub-piston, which moves axially with respect to a cylinder body by rotation of a cap, is used as a rod guide for a piston rod, and a seal member that comes into sliding contact with both the cylinder body and the piston rod with the sub-piston. Is provided. For this reason, since the rod guide (sub piston) for the piston rod is not fixed to the cylinder main body, there is a possibility that the smooth movement of the piston rod may be impaired due to the misalignment of the axis, play, etc. In addition, the sealing member slides on the piston rod on one side of the inner and outer circumferences and slides on the cylinder body on the other side to seal them, so that it is difficult to ensure the sealing performance.

SUMMARY OF THE INVENTION An object of the present invention is to make it possible to smoothly adjust the gas pressure in a cylinder in a state where a gas spring is mounted, and to ensure smooth movement and sealing of a piston rod without changing the mounting length. It is to make.

[0008]

According to the present invention, there is provided a cylinder, a piston rod penetrating through one end of the cylinder and inserted into the cylinder, and a cylinder provided at an insertion end of the piston rod into the cylinder. A piston that slides on the inner surface of the cylinder, and a cylinder mounting member axially engaged with the other end of the cylinder so as to be rotatable relative to the cylinder,
A reaction-adjustable gas spring in which a cylinder is filled with a compressed gas and one of a cylinder mounting member and a piston rod is mounted on a support and the other is mounted on a lid that can be opened and closed on the support. An adjusting nut screwed into the insertion end of the cylinder and prevented from rotating between the cylinder and a sealing member connected to the adjusting nut inside the cylinder and sealing the other end of the cylinder,
By rotating the cylinder, the sealing member is moved via the adjustment nut, so that the gas pressure of the cylinder can be adjusted.

According to a second aspect of the present invention, in the first aspect of the present invention, the cylinder and the adjust nut are prevented from rotating by forming a groove by plastic working from the outside to the inside in the radial direction of the cylinder. It was done.

According to a third aspect of the present invention, in the first or second aspect, the sealing member is a free piston which abuts on an adjustment nut.

[0011]

According to the first and second aspects of the present invention, the following effects are obtained. When the cylinder is rotated with the gas spring attached to the support and the lid, the adjust nut, which is stopped by the cylinder, rotates, and the adjust nut is screwed to the cylinder mounting member and moves in the axial direction. The sealing member moves forward and backward with the movement of the adjusting nut, and expands and contracts the volume of the gas chamber inside the cylinder, thereby adjusting the gas pressure in the cylinder.

An adjusting nut for moving the sealing member inside the cylinder, a detent portion provided on the cylinder for preventing the adjusting nut from rotating, and a screw portion of the cylinder mounting member to which the adjusting nut is screwed; Is built into the cylinder. Therefore, a mechanism for moving these sealing members is not exposed to the outside of the cylinder, so that a chance that dust or the like adheres to them can be eliminated, and the gas pressure can be adjusted smoothly.

[0013] Even when the cylinder is rotated as described above with the cylinder mounting member and the piston rod serving as mounting points for the vehicle body, the cylinder mounting member and the piston rod can move in the axial direction with respect to the cylinder. Absent. Therefore, the mounting length of the gas spring does not change, and the degree of opening (the maximum opening angle and the like) of the lid does not change.

The above-described mechanism for moving the sealing member is provided on the cylinder mounting member side, not on the piston rod side. Therefore, the rod guide and the sealing member for the piston rod are fixed to the cylinder. For this reason, the rod guide slides only between the piston rod and guides it smoothly, and slides only on the piston rod of the seal member to stably seal it.

According to the third aspect of the invention, the following effects are obtained. Since the sealing member is a free piston that abuts on the adjustment nut, the free piston is separated from the adjustment nut and immediately fits freely on the inner surface of the cylinder, so that the sealing performance of the free piston can be easily secured.

[0016]

1 is a sectional view showing a gas spring, FIG. 2 is an enlarged view of a main part of FIG. 1, and FIG. 3 shows a piston.
(A) is a sectional view with a check valve, and (B) is an end view.

The gas spring 10 assists the opening operation force of a lid 2 (not shown), which is a rear door, which is provided on the vehicle body 1 (support) (not shown) so as to be openable and closable in a swinging state, and holds the opening fully. Provided.

The gas spring 10 is, as shown in FIG.
A cylinder 11, a piston rod 12 penetrating through one end of the cylinder 11 and inserted into the cylinder 11, and a piston 13 provided at an insertion end of the piston rod 12 into the cylinder 11 and sliding on the inner surface of the cylinder 11. Having. The piston 13 is inserted into a small-diameter stepped portion at the end of the piston rod 12 via an O-ring or the like, and is fixed by a tip caulking portion of the piston rod 12. A compressed gas such as air or nitrogen gas is sealed in the cylinder 11, and a rod guide 15 made of sintered metal or the like and a gas seal 16 (seal member) are provided in an opening at one end where the piston rod 12 of the cylinder 11 is inserted. ) Is arranged. The rod guide 15 guides the movement of the piston rod 12, and the gas seal 16 prevents gas leakage. In the cylinder 11,
A very small amount of oil necessary and sufficient for lubricating the rod guide 15 and the gas seal 16 and maintaining good sealing performance is sealed.

The gas spring 10 includes a piston 13 and a piston-side gas chamber 20A which does not house the piston rod 12 inside the cylinder 11 and a piston rod 12 inside the cylinder 11.
Is partitioned into a rod-side gas chamber 20B for accommodating the gas. At this time, as shown in FIG. 3, the piston 13 has an annular groove 13A having a wide and deep groove shape in the widthwise middle portion of the outer peripheral surface, and annular grooves at a plurality of circumferential positions on an end surface facing the rod side gas chamber 20B. 13A is opened, and the annular groove 13B is opened.
A check valve 21 made of an O-ring is mounted inside 3A. The check valve 21 is smaller in width than the groove width of the annular groove 13A, has an inner diameter larger than the groove bottom diameter of the annular groove 13A, and has an outer diameter in close contact with the inner surface of the cylinder 11. As shown in FIG. 3A, a gap between the inner surface of the cylinder 11 and the outer diameter of the piston 13 and an annular groove 13 are formed.
The gap between A and the check valve 21 and the flow path 13B make it possible to form a flow path 22 that connects the piston-side gas chamber 20A and the rod-side gas chamber 20B. When the piston 13 moves in the extension direction, as shown in the upper half of FIG. 3A, the check valve 21 abuts against the wall of the annular groove 13A on the side opposite to the flow path 13B to close the flow path 22, and the piston 13 3A, the check valve 21 contacts the wall surface of the annular groove 13A on the flow path 13B side to open the flow path 22, as shown in the lower half of FIG.

The gas spring 10 has a communication portion 23 that connects the piston-side gas chamber 20A and the rod-side gas chamber 20B when the piston 13 is in a certain moving range. In the present embodiment, the communication portion 23 includes a groove 24 formed on the inner surface of the cylinder 11 and extending in the axial direction of the cylinder 11. On the other hand, a rod guide 15 inside the cylinder 11,
A rebound stopper 25 made of resin or the like is inserted in the vicinity of the gas seal 16 so as to be freely movable in the axial direction. The rebound stopper 25 forms an air lock chamber 26 around the piston rod 12, and the rebound stopper 25 extends in the extension direction of the piston 13. The moving end is regulated. The groove 24 of the communication portion 23 is, for example,
Similar to the one described in Japanese Patent No. 158967, the groove is a square groove having a constant groove width and a rectangular cross section, and a damping region 24A having a constant groove depth and a damping throttle region 24B having a groove depth gradually decreasing toward the rebound stopper 25. Are connected in series.

The gas spring 10 connects the cylinder 11 to the vehicle body 1 and the piston rod 12 to the lid 2. At this time, the gas spring 10 has the cylinder mounting member 28 attached to the closing member 27 welded to the other end of the cylinder 11. The cylinder mounting member 28 is
Is axially engaged with the cylinder 11 by a stopper ring 29 provided in the through hole.

Hereinafter, the operation of the gas spring 10 will be described. When the piston 13 is within a certain movement range corresponding to the communication portion 23, the piston-side gas chamber 20A and the rod-side gas chamber 20B on both sides of the piston 13 are connected to the communication portion 23.
As a result, the gas pressure (gas reaction force) of the integral of the cross section of the piston rod 12 acts on the piston 13 in the extending direction, and this gas reaction force becomes an assisting force for opening and operating the lid 2. The extension operation and the compression operation of the gas spring 10 are as follows.

(A) Extension process In the state where the gas reaction force in the extension direction acts on the piston 13,
The check valve 21 closes the flow path 22 provided in the piston 13, and the gas in the rod-side gas chamber 20B flows to the piston-side gas chamber 20A through the communication part 23, so that the gas reaction force moves the piston 13 in the extending direction. As a result, the gas spring 10 is extended, and an extension-side damping force is generated due to the flow resistance when the gas passes through the communication portion 23. Gas spring 10
When the piston 13 moves from the damping region 24A of the communicating portion 23 to the damping throttle region 24B, the braking is gently performed. It is stopped without being. Thereby, the gas spring 10 assists the opening operation force of the lid 2 and holds it fully open.

(B) Compression process The check valve 21 opens the flow path 22 provided in the piston 13, and the gas in the piston side gas chamber 20A flows to the rod side gas chamber 20B through both the check valve 21 and the communication part 23. . Therefore, the closing operation force applied to the lid 2 by the operator causes the gas spring 10 to move the piston 13 smoothly in the compression direction without causing any damping force and to be quickly compressed. Quick closing operation is possible.

However, in the gas spring 10,
In the state of attachment to the body 1 and the lid 2, the temperature difference between cold and warm
The following configuration is provided to compensate for the fluctuation of the reaction force due to the presence or absence of the optional component with respect to the lid 2.

The gas spring 10 has an adjust nut 31 which is screwed into a screw portion 28A provided at the end of the cylinder mounting member 28 to be inserted into the cylinder 11. The outer periphery of the base end 32 of the adjust nut 31 is And a concave engaging portion 32A provided on a part of the outer periphery of the base end portion 32 is engaged with a detent portion 11A provided on the inner periphery of the cylinder 11. A groove is formed in the rotation preventing portion 11 </ b> A by pressing and forming (plastic working) the outer surface of the cylinder 11, and the groove extends in a certain range in the axial direction of the cylinder 11.

The gas spring 10 has a free piston 35 as a sealing member 34 for sealing the piston side chamber 20A inside the cylinder 11, and the tip 33 of the adjusting nut 31 is brought into contact with the back surface of the free piston 35. I'm sorry. The free piston 35 has an O-ring 36 that slides on the inner surface of the cylinder 11.

The gas spring 10 has a piston rod 1
By rotating the cylinder 11 manually or the like in a state where the cylinder 2 and the cylinder mounting member 28 are mounted on the vehicle body 1 and the lid 2, the adjust nut 31 locked to the cylinder 11 is rotated together with the cylinder 11. The adjusting nut 31 is the screw 2 of the cylinder mounting member 28.
The free piston 35 is moved by screwing with respect to 8A and moving in the axial direction, so that the gas pressure of the cylinder 11 can be adjusted.

Therefore, according to the present embodiment, the following effects are obtained. When the cylinder 11 is rotated with the gas spring 10 attached to the vehicle body 1 and the lid 22, the adjust nut 31 stopped by the cylinder 11 rotates, and the adjust nut 31 is screwed into the cylinder mounting member 28. The piston moves and moves in the axial direction, and the free piston 35 as the sealing member 34 is pushed by the adjustment nut 31 and moves forward,
Alternatively, the gas pressure is reduced by the gas pressure, and the volumes of the gas chambers 20A and 20B inside the cylinder 11 are expanded and contracted.

Free piston 3 inside cylinder 11
5, an adjusting nut 31 for moving the adjusting nut 5, a rotation preventing portion 11A provided on the cylinder 11 for preventing the adjusting nut 31 from rotating, and the adjusting nut 3
All the threaded portions 28 </ b> A of the cylinder mounting member 28 into which 1 is screwed are housed in the cylinder 11. Therefore, a mechanism for moving these free pistons 35 is a cylinder 11
It is possible to eliminate the chance of dust or the like adhering to them without being exposed to the outside, and to smoothly adjust the gas pressure.

Even when the cylinder 11 is rotated as described above with the cylinder mounting member 28 and the piston rod 12 being the mounting points for the vehicle body, the cylinder mounting member 28 and the piston rod 12 are Does not move in the direction. Therefore, the attachment length of the gas spring 10 does not change, and the degree of opening (the maximum opening angle and the like) of the lid 22 does not change.

The above-described mechanism for moving the free piston 35 is provided on the cylinder mounting member 28 side,
It is not provided on the side of the piston rod 12. Therefore, the rod guide 15 and the gas seal 16 for the piston rod 12 are fixed to the cylinder 11. Therefore, the rod guide 15 slides only with the piston rod 12 and smoothly guides it, and slides only on the piston rod 12 of the gas seal 16 to stably seal it.

By forming the sealing member 34 as a free piston 35 in contact with the adjustment nut 31, the free piston 35 is separated from the adjustment nut 31 and immediately fits on the inner surface of the cylinder 11.
Sealability by the free piston 35 can be easily secured.

The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration of the present invention is not limited to this embodiment, and the design can be changed without departing from the scope of the present invention. The present invention is also included in the present invention. For example, the sealing member of the present invention is not limited to a free piston, but may be connected to an adjust nut so as to be integrated or connected.

[0035]

As described above, according to the present invention, the gas pressure in the cylinder can be smoothly adjusted while the gas spring is mounted, and the piston rod can be smoothly moved without changing the mounting length. Sealability can be ensured.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a gas spring.

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 shows a piston, (A) is a sectional view with a check valve, and (B) is an end view.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Gas spring 11 Cylinder 12 Piston rod 13 Piston 28 Cylinder mounting member 31 Adjust nut 34 Sealing member 36 Free piston

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) F16F 9/32 P

Claims (3)

[Claims] 1. A cylinder, a piston rod penetrating one end of the cylinder and inserted into the cylinder, a piston provided at an insertion end of the piston rod into the cylinder and sliding on an inner surface of the cylinder, The other end has a cylinder mounting member axially engaged with the cylinder so as to be relatively rotatable. The cylinder is filled with compressed gas, and one of the cylinder mounting member and the piston rod is used as a support, In a reaction force adjusting type gas spring, the other of which is attached to a lid which can be opened and closed on a support, an adjusting nut which is screwed into the insertion end of the cylinder mounting member into the cylinder and which is prevented from rotating with the cylinder. A sealing member connected to an adjustment nut inside the cylinder and sealing the other end of the cylinder, and rotating the cylinder to adjust the adjustment nut. Moving the sealing member via the reaction force adjustable gas spring, characterized in that the adjustable gas pressure in the cylinder. 2. The reaction-adjustable gas spring according to claim 1, wherein the cylinder and the adjusting nut are prevented from rotating by forming grooves formed by plastic working from the outside to the inside in the radial direction of the cylinder. 3. The reaction-force adjusting gas spring according to claim 1, wherein the sealing member is a free piston that comes into contact with an adjustment nut.